Coordinate switch



May 8, 1962 R. NITSCH COORDINATE SWITCH 4 Sheets-Sheet 1 Filed April 2, 1958 way May 8, 1962 R. NITSCH COORDINATE SWITCH Filed April 2, 1958 4 Sheets-Sheet 2 Fig.2

May 8, 1962 R. NIYTSCH COORDINATE SWITCH Filed April 2, 1958 4 Sheets-Sheet 3 y 8, 1952 R. NlTSCH 3,033,939

COORDINATE SWITCH Filed April 2, 1958 4 Sheets-Sheet 4 Fig. 5

United States This invention is concerned with improvements relating to coordinate switches of the type described in copending application Serial No. 573,039, filed March 21, 1956, such switches being applicable in signalling systems and par ticularly in telephone systems.

The various objects and features of the invention will appear from the description which will be rendered below with reference to the accompanying drawings, wherein FIG. 1 shows in schematic manner the principal parts of the switch according to the above noted copending application;

FIG. 2 shows a switch having holding coils disposed in parallel with contact-actuating coils to overcome certain difliculties occurr'mg in connection with a switch according to FIG. 1; t

FIG. 3 shows tube-protected contacts comprising a magnetic shunt as well as contact-actuating and holding coil means according to the invention;

FIG. 4 shows an embodiment in which the magnetic shunt is non-symmetrical with respect to the air gap formed by the contact springs of a tube-protected contact; and

FIG. 5 is an isometric view of a portion of a coordinate ordinate crossing points. Letters A, B and C, D respec-- Y tively indicate line and row contact actuating coils, such coils being respectively common to contact sets disposed in the corresponding lines and rowsand embracing at the crossing points the magnetic circuits of the correspondingly disposed contacts. The terms lines and rows are intended to apply to the two coordinate directions. The contact-energizing or actuating coils are disposed so that one such coil extends on each side of the air gap formed by the contact springs of the respective tube-protected contacts. The joint energization of a line coil and a row coil produces a magneticfiux which is impressed upon the contact set disposed at the crossing point of such coils to cause operative actuation of the corresponding contact ly disposed along the two sides of the contact air gap and a holding coil disposed adjacent one of the actuating coils. Only four crossing points have been shown to give an example; it is understood, of course, that more crossing points may be provided as may be desired or required.

The magnetic shunt, as noted, prevents contact closure responsive to energization occurring only on one side of' the air gap, that is, energization of only one actuating coil alone or in conjunction with the energization offa respectively neighboring holding coil. A contact that had been operatively actuated responsive to energization of two actuating coils may be maintained in its actuated position by energizing the respectively associated holding coil.

atent C 3,d33,939 Fatented May 8, 1962 Other contacts which are not to be operatively actuated may thereby, under certain circumstances, receive energizing flux, resulting in erroneous actuation thereof. This will now be explained with reference to FIG. 1.

-If it is, for example, desired to actuate contact set 1, the line coil A and the row coil C, will be energized; in order to maintain the contact set operated, the holding coil H1 will be energized. If such energization of the holding coil Hi is efiected before disconnection of the row coil C, all contact sets embraced by such row coil C, including the contact set 3, will be energized, since the row coil C lies in such case at one side of the corresponding air gaps while the holding coil H1 lies on the other side thereof. In order to prevent such erroneous operation, a time delay element may be introduced which requires operative connection of a holding coil after disconnection of the row coil lying at the other side of the air gaps of the corresponding contact sets. The introduction of such time element complicates the circuitry required for the switch.

This difliculty may be overcome by arranging the holdin'g coils in parallel with the neighboring actuating coils, as schematically shown in FIG. 2 to explain the principles involved. For example, if the contact set 1 is to be maintained actuated by the operation of the holding coil H1, it will not matter if the row coil C, which cooperated in the contact actuation, is energized upon energization of the holding coil H1 since actuating flux would appear on both sides of the air gap of only the contact set 1, the operative actuation of which is desired. Undesired contacts will not be energized in such a situation.

However, the structure according to FIG. 2 suffers from a basic drawback, appearing incident to multi-utilization of the switch, which is for reasons of economy desirable. For example, if it is in the presence of the energized holding coil H1 (mm'ntaining contact set 1 actuated) desired to operate contact set 4, it will be necessary to energize the line coil B and the row coil D, thereby producing flux flow not only on both sides of the air gaps of the contact springs of contact set 4 but also on both sides of the air gap of contact set 2, the latter flux flowbeing effected by the energization of the row coil D and by the holding coil H1 which had been energized before. Contact set 2, would, accordingly, be energized erroneously.

The invention avoids this drawback by making the energization of a holding coil in conjunction with the energization of an actuating coil lying onthe other side of the corresponding contacts, inefiective to produce actuation of such contacts. This object is realized by disposing the holding coils at a region lying between the ends of the contactsprings and the neighboring actuating coils and spaced from the latter, and carrying to the intervening space and thus to the contactsthe magnetic shunt embracing the corresponding actuating coil and the holding coil, therebyforming an individual shunt circuit for the holding coil.

In case of the structure of the magnetic shunt according to the invention, the holding coil may extend in parallel with the neighboring actuating coil or perpendicular thereto, without producing the previously explained drawbacks.

The operation of the above defined structure will now 7 be explained with reference to FIG. 3, showing in schematic manner, to explain the principle, a contact set comprising a single contact surrounded by two actuating coils and one holding coil and provided with magnetic shunt means according to the invention.

Referring now to FIG. 3, the tube-protected contact comprises a glass tube G into which extends in sealed manner two contact springs F1 and F2. Along the two sides of the air gap La formed by the two contact springs are disposed the actuating coils C and A, respectively,

such coils being shown schematically without regard to the configuration so as to maintain clarity so far as the magnetic conditions are concerned. It is assumed that the line coil, is coil A and that the row coil is coil C. The holding coil H1 is disposed on the same side of the contact air gap La as the line coil A. The ends of the contact springs Fl and F2. which extend from the glass tube G connected with the contact-making portions of the contact spring by a'magnetic shunt comprising the iron paths M1 and M2 and the air gaps L1 and L2.

The flux across the air gap La and'the stray flux respectively occurring across the air gaps Li and L2 are utilized. in such a manner that operative actuation of the contact springs F1 and F2 cannot be eflected responsive to energization taking place only on one side of the contact air gap. Only when energization is present on both sides of the air gap La will there betlux across such air gap which is operative to cause mutual attraction between the contact springs and, accordingly, closure of the contact. It should he considered in this connection, that the fluxes, in the presence of energization on both sides of the air gap La will obviously be additive, while the stray fluxes across the air gaps L1 and L2 will in part, compensate one another, each of the coils A and C driving an individual flux across the two air gaps Ll. and L2 which flow in these air gaps in opposite directions. However, if there is energization only on one side of the air gap, for example, efit'ected by the actuating coil A and the holding coil Hi, the stray fluxes will flow only in one direction across the air gaps L1 and L2; accordingly there will not be any compensation as mentioned before. With proper dimensioning of parts, the flux flowing across the air gap La will be insufficient to effect operative actuation of the contacts.

The saturation plays. a part of its. own; for, once saturation occurs inthe contact springs, a further increase of the electrical excitation cannot become operative, since the magnetic flux in the contact springs does not practically increase. The entire structure, therefore, is to be dimensioned taking into consideration the saturation phenomenon, so as to operate such a coordinate switch with safety factors-as great as possible. It will then be possible to effect atone side ofthe contact gap arr-energization as high as desired, without causing operative actuation of the contact. I

However, in case of a closed contact, other conditions must be considered, since the magnetic impedance across the air gap La becomes negligibly low, considerably wealo ening upon'energization ofthe holding coil Hi the stray fields flowing across theair gaps L1 and L2, while the principal flux flows across the contact springs which are in mutual engagement. ,7

The two iron paths M1 and M2 are in accordance with the invention provided with an angular constriction extending between the line coil A and the holding coil H l, whereby the shunt is, for the formation of a shunt circuit individual to the holding coil, carried to the contacts. This shunt circuit is closed by way of the air gaps L3 and L4. Accordingly, assuming energization of the holding coil Hl while the contact is open, stray fluxes will flow to the air gaps L3 and L4 in the direction of the arrows. Stray fluxes will, of course, also flow across the air gaps L1 and L2. All these stray fluxes will be closed by way of the iron paths M1 and M2 to the end of the contact spring F2 extending from the glass tube G. There is, accordingly, for the holding coil, as compared with the two actuating coils A and C, a-magnetic shunt with considerably reduced impedance, which reduces considerably the flux produced across the air gap La by the holding coil H1.

In case the energization of the. actuating coil C is added to that of the holding coil Hi, the fluxes. across the air gap La will be superposed as in the energization of the actuating coils A and C. However, to the flux produced by the actuating coil is now added only the considerably' weakened flux produced by the holding coil H1. The compensation of the stray fluxes originating from the holding coil Hi and flowing across the air gaps L3 and L4 practically does not take place, since the flux produced by the actuating coil is mainly closed by way of the air gaps Li and L2. The consequence is, that the fluxes which are superposed across the air gap cannot produce operative actuation of the contact. Accordingly, any desired actuating coil may be energized in the pres ence of an energized holding coil, without effecting contact closure, just as no contact closure would be effected by the energization of an actuating coil adjacent to a holding coil. It will, therefore, be seen that the magnetic shunt according to the invention permits, during the holding of a contact set, closure of a desired other contact set by energization of the respectively associated actuating coil, without thereby actuating undesired con tacts and thus making it possible to provide for plural utilization of the switch without troublesome results.

Once the contacts of a contact set are closed, there will be provided a good magnetic connection across the contacting points and stray fluxes occurring will be in effective. The holding coil H1 will easily function to maintain a closed contact in its actuated position.

Thepreventionoi the operative actuation of a contact responsive to energization of anactuating coil on one side of a contact in the presence of an operated holding coil on the other side thereof, therefore depends upon reduction of the energizing effect of the holding coil. This operation may be supported by also reducing the en.- ergization eifect of the actuating coil lying on the side of the contact air gap which is opposite to the holding coil. The flux across the air gap is thereby responsive to energization of the actuating coil and the holding coil further reduced, thus increasing security against operative actuation of the'corresponding contact. In order to assure impression of a suficient flux upon the corresponding contact, responsive to energization of both actuating coils, despite the reduced effectiveness of the energization of this actuating coil (in the case of FIG.

, '3, the coil C), the energization of the actuating coil lying may be increased.

. ance for the contact spring lying outside of the holding alongside theholding'coil (coil A, in case of PEG. 3)

The energization eiiectiveness of the corresponding actuating coil may be decreased, for example, by re ducing the' current conducted thereto or by equipping its winding with fewer turns. the possibility of reducing the energizing etiectiveness by arranging the magnetic shunt non-symmetrical with respect to the contact air gap, so that diflerent magnetic shunt impedances will result for the two contact springs of a contact, producing a lower magnetic shunt impedcoil.

A corresponding structure comprising a non-symmetrical shunt is shown in FIG. 4. This structure corresponds in its basic features to the structure illustrated in FIG. 3. However, the iron paths Ml. and M2 are with respect to the contact air gap La arranged so as to provide an air gap Ll having a cross-sectional area which exceeds that of the air gap L2. The magnetic shunt impedance for the contact spring Fl extending within the actuating coil C, which is largely formed by the air gap Li and the ironpath Ml isthus lower than that for the contact spring P2, lying within theactuating coil A and mainly formed by the air gap L2 and the iron path M2. Accordingly, upon energization of the actuating Y I coil C, a greater part of the flux produced thereby will There is, however, also FIG. 5 shows a portion of a coordinate switch constructed in accordance with the present invention and represented in this figure in manner similar to the structure illustrated in FIG. 3 of US. Patent No. 2,983,792. The portion of the switch shown in FIG. 5, so far as the coils and contact sets are concerned, is apparent from FIG. 2, when rotating such figure by 90, so that the coil C will extend horizontally at the top, the coil B extending vertically at the front, and the holding coil H1 extending horizontally at the top. The magnetic shunt, indicated in FIGS. 3 and 4 by M1 and M2, is formed by mutually interlaced or interlocked pairs of metallic strips.

In order to facilitate the understanding, there shall now be considered the contact set shown in FIG. 5, disposed at the top and frontally, having four sealed-in or protective tube contacts 3/1, 3/2, 3/3, 3/4 (corresponding to contact 3 in FIG. 2). At the opposite ends of this contact set are positioned the pairs of metallic strips N1, N2 and N9, N19, respectively. Adjacent the pair of metallic strips N1, N2 is disposed the pair of metallic strips N3, N4 which embrace the coil C. Next to the pair of metallic strips N3, N4 is positioned the pair of metallic strips N5, N6 which embrace the coil B, followed by the pair of metallic strips N7, N8 which embrace the holding coil Hi, the strips N7, N8 being followed by the metallic strips N9, N10. The pairs of metallic strips N3, N4 and N5, N6 are between the coils C and B angularly bent in the direction of the sealed-in contacts, thus making etfective at this place the air gaps L1 and L2, as indicated in FIGS. 3 and 4. The pairs of metallic strips N5, N6 and N7, N8 are between the coils B and H1 angularly bent in the direction of the sealed-in contacts, so as to form at the corresponding places the air gaps L3 and L4, as shown in FIG. 3. Interlocking of the strips may, for example, be effected by partially slotting each strip along its juncture with an adjacent strip.

Changes may be made within the scope and spirit of the appended claims.

Iclaim:

l. A coordinate switch for use in a signalling system, said switch having tube-protected contact sets respectively comprising contact springs adapted to be actuated by magnetic flux which is caused to flow thereover, the ends of said contact springs extending from the respective tubing thereof, said contact sets being disposed in two coordinate directions, contact actuating coils respectively embracing contact sets positioned in the two coordinate directions and thus embracing the magnetic circuits of the respective contact sets disposed at the respective crossing points, magnetic shunt means extending at each crossing point between the movable parts of the corresponding contact springs and the outwardly extending ends thereof, holding coils which are structurally similar to said actuating coils, said holding coils being respectively embraced by said shunt means and serving upon energization thereof to maintain operatively actuated contact sets in actuated position, said holding coils being disposed at a region extending between the ends of said contact springs and the neighboring actuating coils in spaced relation relative to the latter coils, part of the magnetic shunt which embraces the corresponding actuating coil and the holding coil extending inwardly in laterally spaced relationship between the actuating coil and said holding coil in close proximity to the contacts of the corresponding contact set and thereby forming an individual shunt circuit for said holding coil.

2. A coordinate switch according to claim 1, wherein said magnetic shunt is operative to reduce the energizing effect of the actuating coil which is relatively remote from said holding coil as compared with the energizing effect of the actuating coil which is relatively close to said holding coil.

3. A coordinate switch according to claim 2, wherein the energization input of the corresponding actuating coil is reduced.

4. A coordinate switch according to claim 2, wherein said magnetic shunt means is disposed non-symmetrical with respect to the air gaps formed by the respective contact springs of the corresponding contact sets to produce with respect to the corresponding contact springs differently effective shunt impedance.

5. A coordinate switch according to claim 2, wherein said magnetic shunt means is disposed non-symmetrical with respect to the air gaps formed by the respective contact springs of the corresponding contact sets to produce for the contact spring which extends outside said holding coil a shunt impedance which is lower than that affecting the other contact spring.

6. A coordinate switch according to claim 1, wherein said holding coils are disposed on one side of the contact air gap and in parallel with the actuating coils disposed on the other side of the air gap.

7. A coordinate switch according to claim 2, wherein I said holding coils are disposed on one side of the contact air gap and in parallel with the actuating coils disposed on the other side of the air gap.

8. A coordinate switch according to claim 3, wherein said holding coils are disposed on one side of the contact air gap and in parallel with the actuating coils disposed on the other side of the air gap.

9. A coordinate switch according to claim 4, wherein said holding coils are disposed on one side of the contact air gap and in parallel with the actuating coils disposed on the other side of the air gap.

10. A coordinate switch according to claim 5, wherein said holding coils are disposed on one side of the con tact air gap and in parallel with the actuating coils disposed on the other side of the air gap.

11. A coordinate switch according to claim 1, wherein said holding coils are disposed in parallel with said actuating coil on the identical side of the air gap formed by the contact springs of the contact sets.

12. A coordinate switch according to claim 2, where in said holding coils are disposed in parallel with said actuating coil on the identical side of the air gap formed by the contact springs of the contact sets.

13. A coordinate switch according to claim 3, wherein said holding coils are disposed in parallel with said actuating coil on the identical side of the air gap formed by the contact springs of the contact sets.

14. A coordinate switch according to claim 4, wherein said holding coils are disposed in parallel with said actuating coil on the identical side of the air gap formed by the contact springs of the contact sets.

15. A coordinate switch according to claim 5, wherein said holding coils are disposed in parallel with said actuating coil on the identical side of the air gap formed by the contact springs of the contact sets.

References Cited in the file of this patent UNITED STATES PATENTS 2,187,115 Ellwood Jan. 16, 1940 22,289,830 Ellwood July 14, 1942 2,332,338 Peek Oct. 19, 1943 2,397,123 Brown Mar. 26, 1946 I 2,836,676 Wirth May 27, 1958 2,889,424 Glore et al June 2, 1959 

